Joan Bunbury* - University of Wisconsin - La Crosse
Konrad Gajewski - University of Ottawa
The White River Ash event was a massive volcanic eruption that deposited an extensive tephra layer across southern Yukon about 1200 years ago. Although evidence exists regarding the impacts of this event on the local human population, limited information is available with respect to the effects of the tephra deposition on the aquatic environment. Lake sediment cores were collected from four lakes at varying distances from the source vent within the ash plume for this purpose. Chironomids and sedimentary records revealed that the two lake environments located 100 km from the volcano experienced a greater impact than those 200 km away. The initial impact of the White River Ash event on aquatic ecosystems at sites closer to the source continued for about 60 years, with more prolonged effects on the chironomid community occurring for an additional 40 years. Following recovery of the aquatic ecosystem, chironomid species composition was unchanged from the pre-ash deposition community.